Anodal transcranial direct current stimulation of the right temporoparietal junction enhances the self-effacing bias in Japanese individuals

Abstract

Identifying the cause of social events enables us to understand why our environment interacts with us in a certain way. Although previous studies suggest that the right temporoparietal junction (rTPJ) is associated with internal attribution, the causal relationship remains unclear. The present study, firstly, aimed to investigate whether and how the attributional tendency could change with anodal transcranial direct current stimulation (tDCS) of the rTPJ. Secondly, since Japanese individuals tend to perform self-effacing attribution as a socially adaptive behavior, we examined whether the increased activation of the rTPJ, which facilitates the process of shaping self-concept from another perspective, might increase self-effacing attributions specifically among individuals who are highly sensitive to social rewards. Consistent with these predictions, we found that the increased activation of the rTPJ enhanced self-effacing bias, and this relationship was specifically observed among high reward dependent (RD) individuals. We also revealed that it took a longer time for the high RD participants to avoid self-responsibility for failure after the stimulation. These results suggest that anodal tDCS of the rTPJ could exacerbate self-blaming tendencies in Japanese individuals.